1. Field of the Invention
The present invention relates to lighting including back-up or emergency lighting. More particularly, the present invention relates to an apparatus and method for providing a primary lighting source and a secondary lighting source that provides illumination in the event that power is not available to the primary lighting source.
2. Description of the Related Art
Many different lighting fixtures are known in the art. Examples of such lighting fixtures include flush mounted lighting fixtures such as recessed lights, and surface mounted lighting fixtures such as a ceiling mounted fixture, a wall sconce, a shop light (e.g., a 2′×2′, 2′×4′, 1′×8′, etc. fixture), and the like. As is also known in the art, such lighting fixtures are provided with one or more illumination sources such as an incandescent bulb, a fluorescent bulb, a Light Emitting Diode (LED), and the like. As is further known in the art, the lighting fixture, including the choice of bulb and corresponding circuitry, is designed to receive a single source of power to cause the illumination source to illuminate when desired by a user. For example, a recessed lighting fixture is typically designed with any of a florescent bulb, an incandescent bulb or an LED and provided with a switched source of Alternating Current (AC) power that is controlled by a user when the user desires to illuminate the lighting fixture. More specifically, a typical lighting fixture is connected to a branch circuit of a residential or commercial building and controlled by a wall switch.
However, the lighting fixtures of the prior art include a single illumination source that is capable of receiving power from a single source of power. As such, if the single source of power is unavailable, the illumination source of the lighting fixture cannot illuminate, defeating the purpose of the lighting fixture and frustrating the user. For example, if there is a loss of power to a residential or commercial building, the lighting fixture of the prior art cannot function because the branch circuit that provides power to the illumination source is unavailable.
Accordingly, there is a need for a lighting apparatus that remains able to illuminate upon loss of a single source of power and a circuit for controlling the same.